An FBI agent with a background in cryptography. A brilliant game maker bent on revenge. A deadly battle of wits and wills. An ingenious thriller from the Wall Street Journal bestselling author of The Cipher. FBI agent and former military codebreaker Daniela "Dani" Vega witnesses a murder on a Manhattan sidewalk. The victim is chief of staff for a powerful New York senator. The assassin turned informant is Gustavo Toro...